We talk about gaps in sports all the time. Gaps between linemen in football, gaps in baseball’s outfield where singles turn into doubles and even financial gaps between rich, big-market teams and struggling franchises. But there’s one gap the Natural Resources Defense Council (NRDC) wants to exploit for environmental good: The gap that shows only 13 percent of Americans pay close attention to science news while 61 percent follow sports with a passion.

Based on that discrepancy the NRDC, a nonprofit advocacy group, is trying to use sports as a way to educate the rest of the country about environmental issues. In a partnership with the Green Sports Alliance, the NRDC has seen all five major North American sports leagues join the environmental effort, while individual teams—not all teams are part of the alliance—have started innovative programs to cut energy use and waste while promoting environmental awareness among their fans. Take, for example, the experimental wind turbine that sits atop Progressive Field, home of the Cleveland Indians, or the bags of compost, made from Safeco Field food scraps, given away at a Seattle Mariners Sustainable Saturday game. A new “Game Changer” report released Sept. 5 by the NRDC quantifies exactly how much sports teams have done to improve their environmental profiles, and how far many of them still have to go.

According to Allen Hershkowitz, director of NRDC’s green sports project, the 120-page report presents first-ever case studies of 15 professional sports venues and five marquee events, showing how the $4 billion pro sports industry has the power to change national attitudes towards conservation.

The mix of success, he says, ranges from both environmental wins and major cost savings, with some teams saving more than $1 million annually on operations simply by reducing energy needs and cutting waste streams. In the last five years, professional sports teams have also cut carbon emissions by more than 20 million pounds.

Highlights include:

• Lincoln Financial Field, home of the NFL’s Philadelphia Eagles, is the first stadium in the U.S. capable of generating 100 percent of its energy from renewable sources: a combination of solar panels, a biodiesel/natural gas generator and, soon, 14 wind turbines.

• L.A.’s Staples Center, the busiest arena in North America, produces up to 20 percent of its energy needs with a 1,727-panel solar array that covers 25,000 square feet of the arena’s roof, saving the stadium $55,000 per year. (The Staples Center is one of 18 North American stadiums that now have solar panels onsite.)

• An irrigation system at the San Francisco Giants’ AT&T Park that uses up-to-the-minute local weather data to establish optimal watering times, reducing the amount of water needed to keep the outfield green by 33 percent.

• In addition to their wind turbine, the Cleveland Indians have also introduced a recycling program at Progressive Field which has cut waste in half, kept more than 600 tons of trash from going to a landfill and saved the team $50,000. Oh, and that experimental wind turbine, designed by researchers at Cleveland State University, is four times as powerful as a regular turbine array.

• A new energy-efficiency program that helped save the NBA’s Miama Heat $1.6 million in one year; AmericanAirlines Arena now consumes 53 percent less energy than the average facility of similar size.

With 126 sports teams in five major leagues now part of the Green Sports Alliance, there’s a lot to learn from each other. “We see this as a matter of social responsibility as well as good business,” says Kathy Behrens, the NBA’s vice president for social responsibility. To strengthen both positions, the NBA started a data measurement program this summer to monitor energy and waste usage in arenas. That data can then help successful teams, such as Miami, Portland and Orlando share strategies with the rest of the league. Sixty-eight of these 126 teams are now investigating an energy efficiency plan and 38 of them are using renewable energy in their portfolios, but Hershkowitz says “a lot more needs to be done.”

Only two-thirds of teams have a recycling or composting program in place; Hershkowitz says that those that haven’t gotten on board yet are the teams that face the biggest roadblocks.

“Teams are constrained by the infrastructure of their city,” he says. Recycling and composting programs are common in progressive, relatively prosperous communities like Seattle, Portland and San Francisco, but the Detroit Tigers have limited options in their struggling city. And whereas some teams have programs to either compost or donate their leftover food — NHL teams have donated over 210 tons of unused food to local homeless shelters — others don’t have the same opportunities, as the NRDC found when working with the Pittsburgh Pirates. “The infrastructure for food waste compost is very undeveloped in Pennsylvania,” Hershkowitz says. “There was only one certified composter in all of Pennsylvania.”

On Thursday the Green Sports Summit in Seattle will bring together more than 400 sports executives to discuss environmental issues; Green Sports Alliance director Martin Tull hopes awareness will help shrink the green gap in pro sports. With or without a wind turbine.

Tim Newcomb is a journalist based in the Pacific Northwest covering sports design and technology, culture, infrastructure and entertainment. He writes for Sports Illustrated, Popular Mechanics, TIME and more.